Absorption fin



June s, 1933. R, L MMS 1,912,785

ABSORPTION FIN Filed April 3, 1931 l 1 1 1 l l 1 E1l l lim 1 1 l l SmsjZ0 I 1 E 2 Z7 KW g5.

Patented June 6, .1933

PATENT OFFICE ROY I. MLLS, F CHICAGO, ILLINOIS ABSORPTIGN FINApplication filed April 3, 1931.

The present invention relates to absorption fins and particularly to aconstruction of shells for defining the combustion chambers of heaterswherein the fins are incorporated whereby extreme and sudden changes oftemperature may take place without damage to the heaters.

The term heater is herein used generally and not by way of limitationand in U cludes stoves, furnaces, boilers'and all like apparatus.

Heaters are usually constructed with cast iron or cast steel partsforming the combustion chambers and with metal parts of sheet l iron,sheet steel and even castings and the like about the combustion chambersfor providing the compartments or spaces for the heat conveying elementssuch as air, water and the like. It is well known that expan- 9 sion andcontraction occurs in all heaters 1n accordance with the amount of heatgenerated in the combustion chambers, and `Where amount of heat variesthe expansion and contraction occur with the result that some of theheater parts become distorted, warped, and oftentimes cracked, thusbecoming useless for efficient heating purposes and requiringreplacement.

This is especially true where the heaters are utilized withvintermittent lire such as in oil burners and gas flred heater whereinthe voil or gas fire is on for awhile and off for awhile. The partstherefore are constantly contracting and expanding with the result thatan ordinary heater quickly becomes useless for eiiicient heatingpurposes.'

The present invention is directed to the construction of heatersemploying absorption ins for the combustion chambers whereby temperaturechanges over a wide range may be had without unduly warping, distortingor straining the heaters, thereby lengthening the lives of such heatersto a marked extent.

An object of the present invention is to provide a shell for defining`the combustion chamberof a heater which shell is formed with plaits atintervals, which plaits are closed a'nd opened under expansion and conitraction of theA shell due to temperature Serial No. 527,502.

changes. The provision of these plaits enables expansion of the shellunder high temperature conditions to a marked extent and allowingcontraction thereof when the heat is stopped without distortion, warpingor strain. The plaits open and close with something like pincers actionduring contraction and expansion. Furthermore, the heat-com veyingelements such as air, water and the like pass upwardly along the outsideof the shell and plaits whereby the heat within the combustion chamberis radiated to such heat conveying elements.

The invention is especially useful in connection with intermittent liressuch as oilburners and gas-fired heaters.

An object of the present invention is to provide a heater constructionwherein eX- pansion and contraction of the heater parts may be large dueto a wide range of temperature variations withoutv causing warping,distortion or damage to the heater.

Another object of the invention is to provide absorption fins for usewith heaters whereby considerable amount of expansion and contraction ofthe heater parts may take place without damage to the heater, thusprolonging the life of the heater and of the materials of which it isconstructed.

Another object of the invention is to provide a shell for the combustionchambers of heaters which shell is formed with a plurality of plaitswhich are formed as substantially radially arranged vertically disposedfins extending outwardly from the combustion chamber and with pocketsopening into the combustion chamber whereby maximum radiating surface ispresented to the heat conveying element.

Another object of the invention is to provide a shell for defining thecombustion chambers of heaters which shell is provided. with a pluralityof plaits which plaits have opening and closing movements due to theexpanslon and contraction of the shell in use, because of temperaturevariations thereby prolonging the life of the heater and the shell.

A still further object of the invention is to provide a shell forforming the combustion chamber of a heater with a fin havingbellows-like action during expansion and contraction of the shell.

A still further object of the invention is to provide a combustionchamber shell for heaters which shell is provided with absorption finsso that portions of the shell may have expansion and contractionmovement over a wide range due to temperature changes without damage tothe shell.

Another and further object of the invention is to provide a heater soconstructed that extremes of temperature may be imposed without undulywarping, distorting or straining the heater and whereby the heater maybe useful in effecting rapid changes of temperature in the heatconveying medium or element.

Another and further object of the invention is to provide a shell forthe combustion chamber of a heater which shell is formed with absorptionfins which readily expand and contract with the temperature changeswithin the combustion chamber and wherein a breathing or bellows-likeaction takes place during expansion and contraction.

A still further object of the invention is to provide absorption finsfor heaters which are formed as substantially radially arrangedvertically disposed fins extending outwardly from the combustion chambershell and which fins form pockets which open and close under expansionand contraction of the shell due to temperature variations.

A yet further object of the invention is to provide an eicent and simpleheater for effecting quick temperature changes in heating mediums over awide range and wherein such temperature changes are effected withoutharm to the heater.

Generally speaking the invention contemplates a shell for a combustionchamber of a heater which is formed from relatively thin sheet metalprovided with absorption fins such as plaits struck outwardly from the.inner surface of the shell. The plaits tending to open and close duringcontraction and expansion of the shell in use and the outsides of whichplaits form passages whereby the heating medimn is passed for heatradiating purposes.

The invention further contemplates the formation of such plaits fromsheet metal which plaits have the tops and bottolns of the openings orslots closed and with the intermediate part of the slots of slightlygreater width normally than any other part whereby maximum expansion andcontraction may take place without damage to the shell or other parts ofthe heater.

The above, other and further objects of the invention will be apparentfrom the following description, accompanying drawing and appendedclaims.

The present invention may be embodied in almost any type of heater butfinds especial use in connection with heaters which are intermittentlyfired, such as oil and gas burners and the form of apparatus chosen toexemplify the present invention is illustrati ed as a heater suitablefor installation in a garage whereby air serves as the heat lconveyingmedium.

The accompanying drawing illustrates a hot air heater suitable for usein garages fired by oil, and the views thereof are as follows:

Figure 1 is a vertical sectional view through the illustrated type ofheater.

Figure 2 in an enlarged horizontal sectional view taken substantially inthe plane of line II-II of Figure 1.

Figure 3 is an enlarged front elevational view of a fragmental portionof the shell showing the expansion slot formed by a plait of the presentinvention.

Figure 4 is an enlarged fragmental sectional view of two of the plaitsas the same appear when installed in the illustrated form .of heater.

Figure 5 is a top plan view of the illustrated form of heater.

The drawing will now be explained.

The form of heater chosen to exemplify the present Vinvention is one forheating hot air by means of an oil burner and as illustrated includes abase casting 1 having an upstanding Wall 2 which is provided with apartition 3 having an aperture 4 in the same. The outer surface of theupper end of the npstanding part 2 is rabbeted at 5 to form a shoulderfor supporting the heater.

An oil burner is designated conventionally at 6 and may be of any typeof burner as desired. As the burner forms no part of the presentinvention it is not illustrated or described in detail.

The contour of the heater is illustrated as cylindrical. However, theinvention is susceptible of use with a heater of any contour or shape.

The combustion chamber A .is defined by a shell designated generally asB and fashioned from sheet metal. The shell B is provided with aplurality of surfaces or fillets 7 and aplurality of what are termedherein as plaits 8. The plaits are formed from the metal of which theshell B is constructed by being deformed out of the plane thereof andconsists of two sides 9 and 10 which are connected at the outer marginby a fold 1l and which opens into the interior of the combustion chamberA. The openings of the various plaits 8 into the combustion chamber Aare herein designated as slots 12. The tops and lbottoms of the surfaces7 adjacent the slots 12 are secured together in closed formation as byspotwelding such closure being readily observed in Figures 1 and 3. Theslots 12 are widened approximately intermediate the ends thereofadjacent the zone of greatest heat within the combustion chamber A. Inother words the plaits or slots 8 converge up wardly and downwardlyfrom'a central zone.

The partition 8 forms the lower end of the combustion chamber and theupper end thereof is formed by a top member 13 inserted in the upperlend of the combustion chamber and secured in position as by spotWelding or any other suit-able manner.

The plaits 8 extend substantially radially from the combustion chamber Ain the form of heater illustrated. The outer ends of these plaits 8 aresurrounded by an outer casing 141i.

l'lhere are formed between the plaits 8 the outer surface of the shell Band the inner surface of the casing lll a plurality of poel:- ets 15which in the form of heater illustrated are vertically disposed. Throughthese pockets 15 pass the heating medium such as air. The pockets 15 areopen at the top and bottom so that air may freely pass through the same.The outer casing 14 is secured to the plaits 8 as by spotwelding orWelding of other character. i The lower ends of the plaits areillustrated as cut on diagonal lines 16 which extend downwardly. The

lower ends of the shell B rest on the shoulder l5 formed in theupstanding portion 2 of the msc.

An outlet 17 is provided in one of the surfaces 7 of the inner shell Bfor communicationwith a stack 18 through which the products ofcombustion escape to the atmosphere.

The front of the base member is provided with a cover 19 within whichpass the usual connections to the oil burner 6.

A line 20 in Figure 1 designates the approximate zone of greatest heatwithin the combustion chamber. This zone as will be observed is belowthe chimney outlet 17 and a considerable distance below the top of thecombustion chamber. V

Positioning the chimney outlet 17 below the top results in a zone abovesuch outlet wherein the heat is retained for a considerable period oftime after the oil burner has been shut olf as is customary.

It is well recognized that oil burners and gas fired heaters operateintermittently so that for a time there is high temperature present inthe combustion chamber and then when the lire is turned olf thetemperature falls. Such intermittent firing results. in expansion andcontraction of theparts of the heater to an extent which ordinarilyeventually causes distortion or'warping of such parts to the detrimentof theheater.

The heater provided with the shell B of the present invention and thefins or plaits 8 lends itself readily to such expansion or contractionover a wide range without damage.

The operation of the heater is as follows: The oil burner 6 is firedwhereupon heat medium in the present instance is air. The

air enters the pockets at t-he lower end passing upwardly and thenceoutwardly through the open top for heating the surrounding atmosphere.It has been found that a heater nconstructed in accordance with thepresent invention very readily heats a cold garage 1n a short length oftime such, for instance, as ten orniitteen minutes.

The oii burner continues in operation whereupon the temperature withinthe conibustion chamber risescausingexpansion of shell B i. e. illetsSuch expansion tends to close the slots 12 which movement iscornpensated for by the provision ot the plaits 8 which tend to closeduring such expansion. The provision of the intermediate vwidenedportions of the slots allows greater expansion adjacent the zone ofgreatest or maximum temperature or heat without distortion or strain onthe shell or the fins. When the oil burner is shut olf the combustionchamber tends to cool, whereupon contraction of the fillets 7 takesplace and the parts return to normal position as shown in the drawing.`

The alternate expansion and contraction due to intermittent firing setsup a bellows-like action or a breathing action within the combustionchamber and the plait-s. Such action readily allows expansion andcontraction to a marked degreewithout harm or damage to the shell B orthe fins. The fins being constructed of li ht metal very readily radiatethe heat within the combustion chamber to the heat conducting elementsuch as air so that the surrounding atmosphere is very quickl heatedwhenever the burner 6 is turne on for use.

Movement of the shell B and the fins 8 takes place transversely aswellas longitudinally of the combustion chamber A. This is because of thefact that the upper and lower ends of the fins or plaits are closed.Consequently expansion of the shell B causes movement in the mannerdescribed. This movement is termed herein, for lack of betterdefinition, as breathing or bellows action.

It will be observed that a heater embodying the present invention isvery simple and one which is adaptable to extreme high and lowtemperatures and one wherein this surrounding atmosphere is quicklyheated when the fuel is fired. j l

A fire door is designated at 21 for access to the combustion chamber A.Utilization of the heater embodying the present invention and of theform illustrated would very y is very quickly dissipated through thewall 7 and plaits 8 to the air passing upwardly through 4the pockets 15.

The invention is claimed as follows:

l. A -heater combustion chamber comprising a plaited shell arranged withthe plaits opening into the combustion space and with the portions ofthe shell defining the plaits convergent upwardly and downwardly from acentral zone.

2. A heater combustion chamber comprising a plaited shell arranged withthe plaits opening into the combustion space and with the portions ofthe shell defining the plaits convergentJ upwardly and downwardly from acentral zone, the tops and the bottoms of the plaits being closedtogether.

3. A heater combustion chamber of substantially circular form comprisinga shell formed with circumferentially separated plaits connected byfillets, the fillets defining the generally circular combustion space ofthe chamber, said plaits being open to the combustion space, the edgesof the'plaits being convergent upwardly and downwardly from a centralzone of maximum heat, the tops and bottoms of the plaits being closedtogether, the expansion and contraction of the fillets due totemperature variations setting up breathing actions in the plaits andvertical movement in the shell.

4. A combustion chamber for a heater, said chamber comprising a shell ofgenerally cir.

cular form in plan fashioned to provide plaits and fillets, the filletsspacing said plaits circumferentially and defining a central combustionzone and constituting the inner wall of the combustion chamber, theedges of the plaits diverging downwardly from the top towards a zone ofmaximum heat and diverging upwardly from the bottom towards said zone,the expansion of the fillets causing movement of the edges of the plaitstowards each other and the contraction of the fillets causing movementof the edges of the plaits away from each other.

5. A combustion chamber for a heater, said chamber comprising a shell ofgenerally circular form in plan fashioned to provide plaits and fillets,the fillets spacing said plaits circumferentially and defining a centralcombustion Zone and constituting the inner wall of the combustionchamber, said plaits varying in width from top to bottom with thegreatest width thereof near the zone of maximum heat.

6. A combustion chamber for a heater, said chamber comprising a shell ofgenerally circular form in plan fashioned to provide plaits and fillets,the fillets spacing said plaits circumferentially and defining a centralcombustion zone and constituting the inner wall of the combustionchamber, said plaits varying in width from top to bottom with thegreatest width thereof at substantially midheight of the chamber wherebymaximum eX- pansion and contraction may occur in the zone of maximumheat.

7 A heater combustion chamber comprising a plaited shell ofsubstantially thin sheet metal arranged with the plaits opening into thecombustion chamber, the plaits being spaced and connected by fillets,the fillets defining generally the combustion space of the chamber, thewidth of a fillet between two adjacent plaits being greater than themaximum opening'of a plait, the plaits and fillets being so arrangedthat for a given space a maximum heating surface is presented .to theheat Zone Within the combustion chamber, the plaits being convergent ina direction away from the combustion chamber with the side faces flatand slightly inclined to the direction of heat radiation whereby theradiant energy of the combustible fuel is absorbed by the plaits andpassed on to the heating medium surrounding said combustion chamber.

In testimony whereof I have hereunto sub-- scribed my narne at Chicago,Cook County,

Illinois.

ROY I. MILLS.

